This invention relates generally to antenna assemblies for pulse radar systems and more particularly to an antenna assembly for an active electronically scanned array, also known as an active aperture.
In a typical active aperture for a pulsed radar system, a large number of transmit/receive (T/R) circuits are arranged in a predetermined configuration and connected to an array of forwardly located radiator elements which collectively transmit and receive a beam of RF pulses to and from a target. The beam is typically energized, shaped and directed in azimuth and in elevation under the control of a beam steering controller assembly which forms part of the system.
In a phased array, the radar system sequentially generates RF transmit pulses which are distributed by means of a transmit manifold and microwave power generating circuitry to the array antenna elements. Between transmitted pulses, the radar system receives and processes successive return signals from the same antenna elements. The return signals are then processed and collected through a receive manifold and then processed in the radar system receiver circuitry for target identification and/or display.
In the transmit mode, a microwave transmit circuit in the T/R circuit operates on each RF pulse which is generated and fed to the transmit manifold, and thereafter controls the amplitude and phase of the RF pulse coupled to the antenna elements via a circulator device, a device well known in the art. In the receive mode, a microwave receive circuit in the T/R circuit, operates on each radar return signal coupled from the antenna elements via the circulator to control its amplitude and phase and which is then applied to the receive manifold where the signals are collected from all of the T/R circuits and fed back to RF demodulator circuitry in the system. Accordingly, one transmit circuit and one receive circuit form one transmit/receive channel.
Although transmit and receive circuits embodying a single T/R channel are known to have been fabricated in both separate and common modular packages, in the above-referenced application Ser. No. 09/158,829, (BD-98-012) entitled, "A Dual Channel Microwave Transmit/Receive Module For An Active Aperture Of A Radar System", there is disclosed a dual channel T/R module wherein two discrete T/R signal channels are implemented side by side in a common modular package.
The subject invention is directed to an antenna assembly which can accommodate such a dual channel and other like shaped T/R modules.